RDSolutions Interview Questions and Answers

User Stories follow a structured format to capture requirements in Agile development.

• Start with a simple, clear statement of the feature

• Include the user role, action, and benefit

• Use the format: As a [user role], I want [action], so that [benefit]

• Break down large stories into smaller, manageable ones

Research industry standards, functionality needed, security requirements, and compatibility with existing systems.

• Research industry standards to ensure compliance

• Identify required functionality and features

• Consider security requirements and protocols

• Check compatibility with existing systems

• Evaluate documentation and support provided by API providers

The ER diagram shows the relationships between entities in the application's database.

• The ER diagram displays entities as boxes and relationships as lines connecting them

• Entities represent real-world objects like customers, products, or orders

• Relationships show how entities are connected, such as one-to-one, one-to-many, or many-to-many

• Attributes within entities describe the characteristics of the entity, like name, ID...read more

A high level DFD of the provided UI

• Start with the user interacting with the UI

• Show how data is inputted and processed

• Include any external systems or databases that are accessed

• Display the output or results generated by the UI

SQL joins combine rows from two or more tables based on related columns, enabling complex queries and data analysis.

• INNER JOIN: Returns records with matching values in both tables. Example: SELECT * FROM A INNER JOIN B ON A.id = B.id;

• LEFT JOIN (or LEFT OUTER JOIN): Returns all records from the left table and matched records from the right table. Example: SELECT * FROM A LEFT JOIN B ON A.id = B.id;

• RIGHT JOIN (or RIGHT O...read more

A stored procedure is a precompiled collection of SQL statements stored in a database for reuse and efficiency.

• Encapsulates complex SQL logic for reuse, e.g., calculating total sales.

• Improves performance by reducing network traffic, e.g., executing multiple queries in one call.

• Enhances security by controlling access to data, e.g., granting execute permissions only.

• Supports parameters for dynamic execution, e.g., passin...read more

UNION combines results from two queries, removing duplicates; UNION ALL includes all results, retaining duplicates.

• UNION removes duplicate rows from the result set.

• UNION ALL includes all rows, even duplicates.

• Example of UNION: SELECT column1 FROM table1 UNION SELECT column1 FROM table2;

• Example of UNION ALL: SELECT column1 FROM table1 UNION ALL SELECT column1 FROM table2;

• UNION may be slower due to duplicate removal, whi...read more

To find the third highest salary, use SQL queries with ORDER BY and LIMIT or subqueries.

• Use 'SELECT DISTINCT salary FROM employees ORDER BY salary DESC LIMIT 1 OFFSET 2;' to get the third highest salary.

• Alternatively, use a subquery: 'SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(salary) FROM employees));'

• Ensure the salary column is indexed for bett...read more

Identifying duplicate data involves using SQL queries or data profiling techniques to find repeated entries in a dataset.

• Use SQL queries with GROUP BY and HAVING clauses to find duplicates. Example: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name HAVING COUNT(*) > 1.

• Utilize data profiling tools that can automatically detect duplicates based on defined criteria.

• Implement data validation rules during...read more